A cooperative communication scheme has been provided in a wireless communication system to obtain a spatial diversity gain. According to a cooperative communication scheme, a plurality of nodes may virtually share antennas of other nodes to obtain a spatial diversity gain.
In general, a cooperative communication system includes a source node, a relay node, and a destination node. A relay node generates a relay signal corresponding to a source signal of a source node, and the relay node cooperates with the source node to transmit the source signal and relay signal to a destination node. In such a case, a cooperative diversity gain may be obtained in the destination node.
However, channel state information (CSI) regarding a channel formed between a relay station and a base station may be needed to obtain a cooperative diversity gain. Where a space-time block coding (STBC) scheme is used, although a CSI may not be required, at least two relay stations may be needed. Accordingly, a throughput of a communication system may be reduced to some extent to obtain the cooperative diversity gain.
Currently, a research is being conducted regarding a decode-and-forward scheme. In general, a communication system using a decode-and-forward scheme includes multiple relays. In this case, a source signal transmitted from a source node is transmitted to a destination node via the multiple relays. That is, any one of the relay stations generates a new relay signal by performing the decode-and-forward scheme with respect to a multiple relay signal relayed by a neighboring relay station, and transmits the generated new relay signal to another relay station or a destination node.